Service system and method

ABSTRACT

A system for servicing a fluid system can employ a pressure-reducing source to perform the desired service. The fluid system can be an engine cooling system or other fluid system.

CLAIM OF PRIORITY

This application is a continuation of U.S. application Ser. No.10/058,078, filed on Jan. 29, 2002, now U.S. Pat. No. 6,612,327, whichis a divisional of U.S. patent application Ser. No. 09/817,139 filed onMar. 27, 2001, now U.S. Pat. No. 6,584,994, which is acontinuation-in-part of U.S. patent application Ser. No. 09/735,609, nowU.S. Pat. No. 6,588,445, filed on Dec. 14, 2000, which is acontinuation-in-part of U.S. patent application Ser. No. 09/697,723,filed on Oct. 27, 2000, now U.S. Pat. No. 6,742,535, the entire contentsof which are hereby incorporated by reference.

TECHNICAL FIELD

This invention relates to a system and method of servicing a fluidsystem.

BACKGROUND

Leak testing of fluid systems, such as closed fluid systems, can beperformed periodically. Fluid systems can be subject to corrosion andcan develop leaks. Leaks present in fluid systems can decrease thefunctioning efficiency of the system and can result in excessive fluidloss and, ultimately, system failure. Thus, a fluid system typicallyrequires periodic maintenance.

For example, automotive internal combustion engines typically utilize aliquid cooling system containing coolant, which can include water and acoolant additive, to maintain an optimal operating temperature for theengine. If enough coolant is lost, the engine can overheat withresulting damage to the system and the engine. A cooling system can bedrained of fluid, leak tested and filled with new coolant fluidperiodically to maintain the system. An operator can perform a number ofmanual procedures to perform these services. For example, the operatorcan manually drain a radiator via a drain valve or by removing aradiator hose. With the coolant fluid removed, the operator can removethe radiator cap and attach a vacuum fitting to the radiator orifice totest for leaks. Finally, the operator can remove the vacuum fitting andmanually pour coolant into the radiator while observing the coolantlevel until the radiator is filled.

SUMMARY

In general, the invention features an apparatus and method of servicingfluid systems. The fluid system can be a closed fluid system, such as,for example, an engine cooling system, engine oil system, hydraulicsystem or brake system. Servicing can include draining, filling or leaktesting the fluid system. The apparatus can employ a pressure-reducingsource to perform one or more of the desired services.

In one aspect, the invention features an apparatus for servicing a fluidsystem. The apparatus includes a body and a connector on the body forforming a seal with an orifice of the fluid system. The body includes afirst lower port fluidly connected to a first upper port by a firstchannel and a second lower port fluidly connected to a second upper portby a second channel.

In another aspect, the invention features a system for servicing a fluidsystem. The system can include a service apparatus including a body anda connector on the body for forming a seal with an orifice of the fluidsystem. The body includes a first lower port fluidly connected to afirst upper port by a first channel, and a second lower port fluidlyconnected to a second upper port by a second channel.

In another aspect, a system for servicing a fluid system includes areservoir capable of containing a fluid and having a reservoir orifice,and a service apparatus. The service apparatus can include a body and asealing member on the body configured to form a seal with the reservoirorifice. The body includes a first lower port fluidly connected to afirst upper port by a first channel. The system can include apressure-reducing source fluidly connectable to the second upper port.The pressure-reducing source can be a venturi. In other embodiments, thesystem can include a drainage wand having a sufficient diameter andlength to enter the service port.

The service apparatus can include a second lower port fluidly connectedto a second upper port by a second channel and a valve proximate to thesecond channel that can stop fluid flow in the second channel when fluidenters the second lower port.

The reservoir can be a container having an internal volume and apressure regulator. The pressure regulator can be a pressure reliefvalve operable to vent the internal volume when a pressure in theinternal volume decreases below a threshold value. In certainembodiments, the pressure relief valve includes a cylindrical body, apoppet within the body, and a vent control knob. The cylindrical bodycan have an outer wall, an inner wall, and a channel fluidly connectinga first port and a second port. The poppet can be within the body andcan be biased to close the channel, the poppet opening the channel whenthe pressure in the internal volume decreases below the threshold value.The vent control knob can be threadably attached to the first port, andcan be capable of engaging and opening the poppet.

In another aspect, the invention features a method for servicing thefluid system. The method includes draining a fluid from the fluidsystem, connecting the service apparatus onto an orifice of the fluidsystem, changing the pressure of the fluid system through the secondupper port, monitoring the pressure within the fluid system for apredetermined amount of time to detect a leak in the system and applyinga reduced pressure to the second upper port to withdraw fluid from afluid source fluidly connected to the first upper port, through thefirst channel and into the fluid system.

The apparatus can include a valve proximate to the second channel thatstops fluid flow in the second channel when a fluid enters the secondlower port. The valve can be a fluid-detecting valve and can include afloat ball. The first upper port can include a valve.

The connector can include a sleeve made of resilient materialsurrounding the body. The sleeve can form a seal between the apparatusand the service port. The apparatus can include a sleeve compressorexternal to the body and in contact with the sleeve.

The fluid system can be a cooling system, such as an engine coolingsystem. The orifice can be a radiator orifice, such as a radiator fillport.

The system for servicing a fluid system can include a pressure gaugeconnectable to the second upper port. The system for servicing a fluidsystem can also include a pressure-reducing source fluidly connectableto the second upper port. The pressure-reducing source can be a venturi.In certain embodiments, the system for servicing a fluid system caninclude a hose connectable to the first upper port or the second upperport of the apparatus or a drainage wand having a sufficient diameterand length to enter the orifice and enter the fluid system.

In another aspect, the invention features a method for draining a fluidsystem. The method includes fluidly connecting a drainage wand to afirst upper port of a service apparatus, the apparatus being sealablyconnected with a reservoir and the drainage wand being inserted in anorifice of the fluid system, and applying a reduced pressure to a secondupper port of the service apparatus to withdraw fluid from the fluidsystem into the reservoir.

In another aspect, a method of draining a fluid system includes fluidlyconnecting a drainage wand to a first upper port of a service apparatus,sealably connecting the service apparatus with a reservoir, insertingthe drainage wand into a service port of a fluid system, and applying areduced pressure to a second upper port of the service apparatus towithdraw fluid from the fluid system into the reservoir.

In another aspect, the invention features a method for filling a fluidsystem. The method includes applying a reduced pressure to a serviceapparatus to withdraw fluid from a fluid source fluidly connected to theservice apparatus, through the apparatus, and into the fluid system. Theservice apparatus can include a valve proximate to a channel that stopsfluid flow in the channel when the fluid enters the channel. The reducedpressure can be applied continuously to the service apparatus.

In another aspect, an apparatus for servicing a fluid system includes abody including a first lower port fluidly connected to a first upperport by a first channel, and a sealing member on the body configured toform a seal with an orifice of the fluid system when placed on theorifice. The seal with the orifice can increase when a reduced pressureis applied to the first upper port.

The body can include a second lower port fluidly connected to a secondupper port by a second channel and a valve proximate to the secondchannel that stops fluid flow in the second channel when a fluid entersthe second lower port. The valve can be a float valve. The float valvecan include a float ball, a tapered plug, a pointed rod, a flappervalve, a poppet, or a hollow float. The first upper port can include avalve.

The sealing member can include a resilient material. The sealing membercan form a sealing surface perpendicular to the first channel. Thesealing member can include a flat rubber disk, a sizing ring and ano-ring, a bladder, a tapered member, or a resilient ring with a sealinglip, the lip contacting an inner surface of the orifice to form theseal.

The sealing member can include a sleeve. The apparatus can include asleeve compressor, which can be threaded, external to the body and incontact with the sleeve. A threaded bolt can extend into the body andcan be arranged to move the sleeve compressor thereby compressing thesleeve. In certain embodiments, the apparatus can include a cam externalto the body arranged to move the sleeve compressor thereby compressingthe sleeve.

In another aspect, a method for servicing a fluid system includesdraining a fluid from the fluid system, sealing a service apparatus ontoan orifice of the fluid system by reducing pressure in the system, andfilling the system with a fluid source fluidly connected to the firstupper port.

In another aspect, a method for filling a fluid system includes applyinga reduced pressure to a service apparatus to withdraw fluid from a fluidsource fluidly connected to a service apparatus, through the apparatus,and into the fluid system, the service apparatus forming a seal with thefluid system when the reduced pressure is applied.

The service apparatus can serve as a single tool for multi-functionservicing of fluid systems. For example, the apparatus facilitatesdraining, leak testing, and filling of any contained fluid system, suchas an internal combustion engine cooling system. The apparatus can alsoinclude a simple, automatic valve that allows the operator to avoidoverfilling the fluid system, such as a radiator, or a drainagereceptacle. Thus, an operator can use the apparatus without constantlymonitoring its operation. In addition, by continuously applying areduced pressure during filling, the occurrence of pockets of air,sometimes known as air locks, in the system can be reduced. Continuousapplication of reduced pressure combined with the automatic valve canallow systems of various sizes to be filled completely and rapidly. Theapparatus also allows a fluid system to be completely filled withoutexchanging hoses or other attachments during the process. Thecontainment of various features in the apparatus can provide costadvantages over other devices used for similar purposes such asautomated service devices. The apparatus including the sealing membercan form a seal with the orifice of the fluid system when the apparatusis placed on the orifice. The apparatus has a mass sufficient to applypressure to the sealing member for the seal. When reduced pressure isapplied to the apparatus, the seal is improved, simplifying the use ofthe apparatus to service a fluid system. The self-sealing apparatus canhave a lower vertical profile than an adjustable apparatus, and can haveno moving parts other than valves.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic drawing depicting a section view of a serviceapparatus.

FIGS. 2A and 2B are perspective views of a service apparatus.

FIG. 3 is a perspective view of a service kit used in a drain mode.

FIG. 4 is a perspective view of a service kit used in a test and fillmode.

FIG. 5 is a schematic drawing depicting a section view of a serviceapparatus.

FIGS. 6A and 6B are perspective views of a service apparatus.

FIG. 7 is a schematic drawing depicting a pressure regulator.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

Referring to FIG. 1, service apparatus 100 includes body 10 with reducedpressure channel 15 having lower reduced pressure port 20 and upperreduced pressure port 25, fluid channel 30 having lower fluid port 35and upper fluid port 40 and connector 45 on body 10. Upper reducedpressure port 25 may have a hose fitting 48 that is sufficiently sizedto accept a section of flexible hose (not shown). Reduced pressurechannel 15 can contain valve 50 that closes channel 15 when fluid enterslower reduced pressure port 20. Valve 50 can include float ball 55proximate to lower reduced pressure port 20 that is buoyant in the fluidof the fluid system. Float ball 55 sits in recess 56 such that reducedpressure channel 15 passes substantially over ball 55. Fluid can enterlower reduced pressure port 20 or recess 56 to cause ball 55 to rise andclose channel 15. Lower reduced pressure port 20 can be on a side of theapparatus. In other embodiments, lower reduced pressure port 20 can beat the end of the apparatus.

Connector 45 is sized to fit snugly into a fluid system orifice (notshown). Sleeve 60, which is composed of resilient material, can befitted around the connector and held in place at the lower end of thebody by retainer 80. Sleeve compressor 70 can be movably attached bythreads to the outside of body 10 and positioned above bearing 75 thatcontacts sleeve 60. Sleeve compressor 70 can be a knob that is rotated,forcing the knob toward sleeve 60, thereby compressing the sleeve andexpanding it outwardly to seal with the orifice. In other embodiments,the sleeve compressor can be movable by a threaded bolt extending intothe body (not shown) that can be tightened to compress and therebyexpand the sleeve. In another embodiment, the sleeve compressor can bemoved by a cam (not shown) external to the body. The cam can be rotated,for example with a lever, forcing the sleeve compressor into the sleeve,thereby causing the sleeve to compress and expand. In order toaccommodate different diameter fluid system orifices, sleeve 60 can bereplaced with a sleeve having a smaller or larger diameter by removingretainer 80, slipping sleeve 60 off of body 10, and installing a newsleeve having a different diameter. Alternatively, a supplemental sleeve(not shown), which has an inner opening that corresponds to the outerdiameter of sleeve 60, can be slipped over the outer surface of sleeve60 to accommodate a larger diameter system orifice. In certainembodiments, a sealing member can form the seal with the fluid systemorifice.

Referring to FIGS. 2A and 2B, service apparatus 100 includes body 10,connector 45, sleeve 60, lower reduced pressure port 20, upper reducedpressure port 25, lower fluid port 35 and upper fluid port 40. Upperfluid port 40 is connected to a valve 65 to control fluid flow or leaktest the system. Valve 65 can be a ball valve, as shown. Valve 65 canconnect to a fluid hose (not shown) via quick connect fitting 90. Upperreduced pressure port 25 may connect to hose fitting 48 that connects toa pressure-reducing source (not shown). Retainer 80 may be attached tothe bottom of the body by screws.

As shown in FIG. 3, service apparatus 100 can be configured as a system400 to drain fluid from fluid system 310. For example, as shown in FIG.3, fluid system 310 can include a radiator of a cooling system of aninternal combustion engine, in which case coolant is drained from thesystem. Service apparatus 100 is sealed to orifice 405 of reservoir 410.Sleeve compressor 70 is rotated to create an airtight seal betweenapparatus 100 and orifice 405. Valve 65 can be positioned to seal upperfluid port 40. Drainage wand 415 is connected to upper fluid port 40 andinserted in system 310. Drainage wand 415 can be a flexible hose or aplastic tube having a diameter sufficiently small to be inserted throughorifice 315 of system 310. Alternatively, a first end of a hose isconnected to upper fluid port 40 and the other end of the hose isconnected to drainage wand 415. One end of hose 325 is connected toupper reduced pressure port 25. The other end of hose 325 is connectedto a pressure-reducing source 335, such as a venturi, which can includea muffler to reduce noise or a section of hose extending from case 350.When pressure-reducing source 335 is a venturi, it is connected to airsource 355 to generate a reduced pressure in reservoir 410. Reservoir410 can be a container that withstands the reduced pressure applied tothe system without collapsing or includes a pressure regulator or otherrelease mechanism to avoid collapse. For example, the pressure regulatorcan be a pressure relief valve 700, as described below and shown in FIG.7, which can prevent the pressure of the internal volume of thecontainer from decreasing below a threshold reduction from ambientpressure that would otherwise cause the container to collapse.

In operation, the pressure can be reduced by, for example, 1-25 inchesof mercury to drain the system. Valve 65 is opened, thereby applying thereduced pressure to system 310. The reduced pressure pulls fluid fromsystem 310, through hose 320 and apparatus 100 and into reservoir 410.If the fluid has filled reservoir 410, the float ball rises in thefluid, thereby blocking the application of reduced pressure and stoppingthe flow of fluid. Reservoir 410 can be sealed and the used fluid can bedisposed of or recycled.

When servicing fluid system 310, other draining methods may be employed.For example, a drain valve (not shown) in the system, for example, atthe bottom of a radiator, can be opened to drain the system by gravity.In other cases, a system hose (not shown) may be removed to allow thefluid to drain from system 310.

Referring to FIG. 4, apparatus 100 can be used to test system 310 forleaks. With radiator 310 drained, or partially drained of fluid, serviceapparatus 100 can be sealed to orifice 315 of system 310. Reducedpressure is applied to system 310 with valve 65 in a closed position.The occurrence of air pockets can be reduced by reducing the pressure inthe system as much as possible. The pressure can be reduced by, forexample, 25 inches of mercury or more. Valve 360 is then closed to stopapplication of the reduced pressure to the system and seal the systemfor leak testing. For a predetermined period of time, such as 5-10minutes, the pressure of the system can be monitored at gauge 340. Achange of pressure indicates a leak in system 310. A leak in the systemcan be repaired before filling it with replacement fluid.

Referring to FIG. 4, system service apparatus 100 can be part of asystem 300 to fill a fluid system with fluid. For example, as shown inFIG. 4, fluid system 310 can include a radiator of a cooling system ofan internal combustion engine, in which case coolant is added to thesystem. The system can be empty, partially filled, or nearly filled whenthe apparatus is used to fill it. Service apparatus 100 is installed inorifice 315 of system 310. Sleeve compressor 70 is rotated to create anairtight seal between the apparatus 100 and orifice 315. One end of hose320 is connected to upper fluid port 40. The other end of hose 320 isplaced inside fluid source 330, which can be a container filled with afluid. One end of a second hose 325 is connected to upper reducedpressure port 25. The other end of hose 325 is connected to pressurereducing source 335. As shown, service apparatus 100 may be packaged ina case 350 that houses pressure reducing source 335 and pressure gauge340. When pressure-reducing source 335 is a venturi, it is connected toair source 355 to generate a reduced pressure in system 310. The reducedpressure pulls fluid from reservoir 330 through hose 320 and apparatus100, and into system 310. The reduced pressure can be appliedcontinuously to the apparatus 100 during the filling process. As thefluid level in system 310 rises and reaches orifice 315, the fluidcauses float ball 55 to rise and close the channel in the apparatus,stopping the reduced pressure applied to the system and, consequently,stopping the flow of fluid into system 310 through hose 320. The systemcan be run after the filling process has stopped, while the reducedpressure is being applied, to remove air that may continue to reside inthe system. Alternatively, apparatus 100 can be removed from the system,the system can be run for, for example, 1-5 minutes, to move air pocketsin the system, and apparatus 100 can be used to reduce pressure in thesystem and fill the system a second time. This process can be repeatedto further reduce the amount of air in the system. After filling iscomplete, apparatus 100 can be removed from system 310.

The body 10, valve 65, valve 360, pressure reducing source 335, pressuregauge 340, reservoir 410, and receptacle 330 can be made from rigidmaterials such as machined, molded or cast metal or plastic. The sleeve60 and hose 320, hose 325, and wand 415 can be made of resilientmaterials such as a rubber or plastic composition. The float ball 55 canbe made of a material that has a specific gravity that is lighter thanthe system fluid, yet heavy enough to avoid blocking the reducedpressure channel 15 in the absence of the fluid. For example, the floatball can be made of polypropylene.

Referring to FIG. 5, service apparatus 500 includes body 10 with reducedpressure channel 15 having lower reduced pressure port 20 and upperreduced pressure port 25, fluid channel 30 having lower fluid port 35and upper fluid port 40 and connector 45 on body 10. Reduced pressurechannel 15 can contain valve 50 that closes channel 15 when fluid enterslower reduced pressure port 20. Valve 50 can include float ball 55proximate to lower reduced pressure port 20 that is buoyant in the fluidof the fluid system. Float ball 55 sits in recess 56 such that reducedpressure channel 15 passes substantially over ball 55. Fluid can enterlower reduced pressure port 20 or recess 56 to cause float ball 55 torise and close channel 15 when float ball contacts float ball seal 57.The connector 45 configured to form a seal with an orifice of the fluidsystem can include sealing member 62. Sealing member 62 on body 10 isconfigured to form a seal with the orifice when placed on the orifice(not shown). The sealing member can form the seal without mechanicaladjustment of sealing member dimensions.

Sealing member 62 can be a ring of resilient material, for example, acontinuous ring, which is fitted around the body 10. Sealing member 62can be held in place at the lower end of the body 10 by retainer 80. Theresilient material can include a rubber, such as butyl rubber orsilicone rubber. The sealing member can have a hardness between Shore OOdurometer of 20 and Shore A durometer of 80, or Shore A durometer of 20to 60, such as a Shore A durometer of 40.

Sealing member 62 can seat onto a fluid system orifice or reservoirorifice to form a seal. The seal can be improved by applying reducedpressure to the upper reduced pressure port 25. When orifice is aradiator neck of a cooling system, the apparatus can form a seal withsmallest orifice 91, typically having an inside diameter of 1.10 inches,and with largest orifice 92, typically having an inside diameter of 2.70inches.

Sealing member 62 can have a flat surface or a square shape such as agasket. The gasket can be sized to seal with orifices, such as radiatornecks, ranging in inside diameter from 1 inch to 2.5 inches. In otherembodiments, sealing member 62 can be tapered, such as a plug having awide surface adjacent to the upper ports, which tapers to a narrowsurface adjacent to the lower ports. The taper of the plug can allow theapparatus to seal with different sized fluid system orifices. In otherembodiments, sealing member 62 can be a bladder having an annular ordonut shape, which can be filled with a gel, such as, for example, asilicone, to give the sealing member a compliant texture that conformsto the shape of the orifice. The bladder can be sized to fit variousdiameter fluid system orifices. The bladder can be bonded to body 10with an adhesive instead of using retainer 80 to affix the bladder tothe body. Alternatively, the bladder can be bonded to a ring (notshown), which can attach to the body. In other embodiments, sealingmember 62 can be an o-ring combined with a sizing ring that holds theo-ring in place. The o-ring and sizing ring can have a range of sizes toaccommodate fluid system orifices of varying diameters. The sizing ringcan fit between the o-ring and the body to seal with the fluid systemorifice. In other embodiments, sealing member 62 can be an elongatedplug having a lip, such as a wedge-shaped sealing lip, extending awayfrom the plug that forms a seal with an inner surface of the orificewhen inserted into the orifice. The sealing lip can be sized toaccommodate a range of orifice inside diameters, for example, from 1.0inch to 1.2 inches. The plug with sealing lip can have several differentsizes to accommodate other orifice inside diameters, such as 1 inch, 1.5inch, 1.75 inch and 2.0 inch orifices.

Referring generally to FIGS. 6A and 6B, two perspective views of theapparatus illustrated in FIG. 5 includes body 10, upper reduced pressureport 25, upper fluid port 40, connector 45, lower reduced pressure port20 and lower fluid port 35. Connector 45 includes sealing member 62 andextends perpendicularly from the body to position the lower fluid portsdown into the neck of a fluid system orifice. Sealing member 62 is fixedto the body 10 by retainer 80. Float ball 55 rests in recess 56 when nofluid is present.

Referring to FIG. 7, a pressure relief valve 700 penetrates wall 702 ofthe reservoir. Pressure relief valve 700 includes a cylindrical body705, a vent control knob 710, a mounting nut 715, a sealing member 717,a poppet 720, a poppet holder 725, and a poppet spring 730. Vent controlknob 710 is external to the reservoir and poppet 720 is internal to thereservoir. Mounting nut 715 presses wall 702 into sealing member 717 toseal the internal volume of the reservoir from the external atmosphere.

The body 705 includes an outer wall 735, an inner wall 740, a threadedvent port 745, neck 750, a sealing surface 755, and a threaded poppetport 760. The outer wall 735 of the neck 750 includes threads forattaching the mounting nut 715. The threaded vent port 745 threadablyattaches the vent control knob 710 to the body 705. The threaded poppetport 760 threadably attaches the inner wall 740 to the poppet holder725. The poppet holder 725 includes an elongated cylindrical aperture765.

The poppet 720 has a shaft 775 that fits into the aperture 765. Thepoppet 770 also has a head 780 with a beveled edge 785 that retains asealing ring 787 which contacts the sealing surface 755 of the body 705when the valve is in a closed position. The poppet spring 730 upwardlybiases the poppet 720 in the closed position, as shown.

The poppet 720 moves from the closed position to an open position whenthe pressure internal to the reservoir is reduced below a thresholdlevel relative to pressure external to the reservoir. The thresholdlevel for opening the poppet 720 is determined by the spring constant ofthe poppet spring 730. The spring 730 can be selected to open before thereduced pressure internal to the reservoir collapses the reservoir. Forexample, a threshold level of 7 to 9 inches of mercury can collapse aplastic container, a result that can be avoided with the pressurerelease valve.

Under circumstances where maintaining the pressure release valve in anopen position is desired, such as when coolant is poured from thereservoir, the poppet 720 can be maintained in an open position byscrewing the vent control knob 710 into body 705 to hold the poppet 720in an open position.

A number of embodiments of the invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention. Forexample, the apparatus can be used to drain, leak test, and fill avariety of closed fluid-containing systems, such as engine coolingsystems, engine oil systems, hydraulic systems or brake systems.Accordingly, other embodiments are within the scope of the followingclaims.

1. A method for filling a fluid system comprising: applying a reducedpressure to a service apparatus to withdraw fluid from a fluid source,through the apparatus, and into the fluid system, the apparatus beingsealably connected to the fluid system by a sleeve made of resilientmaterial wherein the service apparatus includes a valve proximate to achannel that stops fluid flow in the channel when the fluid enters thechannel.
 2. The method of claim 1 wherein the apparatus furthercomprises a lower port fluidly connected to a upper port by a secondchannel.
 3. The method of claim 1, wherein the reduced pressure isapplied continuously to reduce the occurrence of air locks in thesystem.
 4. The method of claim 1, wherein the system is a coolingsystem.
 5. The method of claim 1, wherein the valve is a float valve. 6.The method of claim 5, wherein the float valve includes a float ball.